Becoming the new lead singer in the pioneering English progressive-rock band Yes is a daunting task for any musician.

The group, which next year celebrates its 45th anniversary, has recorded more than two dozen albums since its self-titled 1968 debut. Along the way, it has crafted some of the most intricate and technically challenging songs in rock history.

Having a high vocal range and pinpoint dynamic control, like original Yes singer Jon Anderson, is mandatory. So is the ability to memorize and convincingly perform such unconventional lyrics as: Along the edge of this airfield / The old prop-shaft airliners stand / Altimeters reading zero / Formless memories lingering (from last year’s “Fly From Here”); and: In and around the lake / Mountains come out of the sky / And they stand there / One mile over (from 1971’s “Roundabout,” the second U.S. Top 40 hit of Yes' career).

Yet, while Jon Davison got lots of practice as the lead singer in the San Diego Yes tribute band Roundabout back in 2005 and 2006, when he joined the real Yes earlier this year, he didn’t even audition.

“We were pretty certain he’d fit in well. We met and chatted over lunch,” said bassist-singer Chris Squire, 64, the only founding member of Yes still on board.

Squire chuckled. "It's kind of funny -- we went from Anderson to David to Davison."

Davison, 41, had several things going in his favor.

Squire is an admirer of Davison’s work with Glass Hammer, a veteran American prog-rock band that counts Yes among its biggest influences. So is Foo Fighters drummer Taylor Hawkins. A friend of both the oldest and the newest members of Yes, Hawkins began lobbying Squire and Yes’ manager on Davison’s behalf, after acute respiratory failure prompted veteran Yes singer Anderson to bow out in 2008.

But Hawkins’ efforts didn’t pan out. Instead, Anderson’s role was filled by Benoit David, the lead singer in the Canadian Yes tribute band Close t the Edge, whom Squire discovered on YouTube. Rather than be dismayed by this turn of events, Davison was encouraged.

“It showed they were open to working with a Yes tribute band singer,” said Davison, who in the 1990s was the bassist in the Seattle band Sky Cries Mary. “I felt that if anything should happen in the future, that was a possibility for me. So the idea was there, although I’d kind of given up, because Benoit was doing a good job.”

David has performed twice here with Yes at Humphrey’s Concerts by the Bay, where the band plays Saturday for the first time with Davison. The Canadian singer left Yes last year — in a strange twist that mirrors Anderson’s departure before him — because of respiratory failure.

Regardless, the call to join Yes came as a happy surprise to Davison, who lives in Laguna Beach with his wife.

"I wasn't even aware or anything until Taylor called me and said that Chris had asked for my phone number," Davison said.

he chuckled when asked if, to speed his entry into Yes, he’d stuck needles into a voodoo doll of David.

“No,” Davison said.

“But I have a positive personality and I’m just a dreamer. I am still very surprised. I still wake up some mornings and think: ‘Wow! I’m in Yes.’ They’ve always been my favorite band since I was 12, when I heard (the band’s chart-topping 1983 single) ‘Owner of a Lonely Heart.’ Then I bought (Yes’ 1973 triple-album) ‘Tales From Topographic Oceans,’ and it was like opening the Bible.”

For his part, Squire now wishes he would have listened to Foo Fighters drummer Hawkins when he recommended Davison in the first place.

"Strangely enough, Jon's name came up when we started working with Benoit," Squire recalled. "In fact, my friend, Taylor Hawkins, hadbeen telling me for years: 'If you ever need a replacement (singer), I know exactly the guy.

“Jon has been a fantastic find and he’s a really good singer I wish we had got him earlier, because then we wouldn’t have had to go through the Benoit period, not that there was anything wrong with that. But we’re lucky to be where we are now. It’s been a very pleasant experience with Jon. He’s pretty flawless and he’s got a good head for this job. It feels like he’s been with us for a long time, strangely enough. We haven’t had problems and I don’t foresee having any.”

Squire is uncertain what, if anything, Yes will do to mark its 45th anniversary next year.

Alan White, who replaced original Yes drummer Bill Bruford in 1972, periodically leads his own band, White. Keyboardist Geoff Downes, who came on board in 1980 for one album and tour, rejoined Yes last year. He and guitarist Steve Howe, who joined Yes in 1970, are also member of the band Asia, which the two co-founded in 1981 with Carl Palmer and John Wetton. Squire, meanwhile, recently formed a side project with former Genesis guitarist Steve Hackett.

In the meanwhile, original Yes singer Anderson has been doing solo tours and touring in an acoustic duo with Rick Wakeman, who replaced original Yes keyboardist Tony Kaye back in 1971.

“One thing we’ll probably be doing is making a new Yes studio album,” Squire said. “It will be our first album with Jon singing.”

That prospect is music to Davison’s ears.

“This has been a win-win situation for me,” he said. “If there had been only one rehearsal and I had to walk away, I would have been so grateful. So I’m very grateful at the opportunity I’ve been given. We all get along great in the band, and (Yes’) fans have been so warm and welcoming.”

For art-rock fans, Saturday's Yes concert here should be a double-treat.

The opening act is Procol Harum, the English band best known for its Bach-inspired 1967 hit, "A Whiter Shade of Pale," but also responsible for such landmark albums as "A Salty Dog," "Home," "Broken Barricades" and "Grand Hotel." The current edition of Procol Harum features just one original member, singer-pianist Gary Brooker.

"I don't thin we ever toured (before) with Procol Harum," Squire said. I don’t recall ever having met them or having been on the road with them, at all, so it's quite weird. I don't think we've ever even been on same bill with them at a festival."

Squire not only plans to continue touring until he drops, he even predicts that an iteration of yes could exist 100 years from now. He still sounds taken aback that drum great Bruford, who left Yes in 1972 to join King Crimson, retired in 2009 (at the age 60) from touring and recording.

"I was surprised when bill announced he was retiring from performing; I didn't think musicians ever really retired until they were retired by natural causes," Squire said.

"I don't know. Did Bill retire to do something else? 'I think I'll retire from playing bass guitar and become a hair dresser.' But good luck to him. I'm enjoying playing music as much as I ever have, and creating new music and playing live to people who still love to hear the music Yes does. I'm grateful."